  Conjugate operator $T$ of 1D-harmonic oscillator $N=1/2 (p^2+q^2-1)$ is
defined by an operator satisfying canonical commutation relation $[N,T]=-i$ on
some domain but not necessarily dense. The angle operator $T_A=1/2 (\arctan
q^{-1} p+\arctan pq^{-1} )$ and Galapon operator $T_G=i
\sum_{n=0}^\infty(\sum_{m\neq n}\frac{(v_m,\cdot) }{n-m}v_n)$ are examples of
conjugate operators, where ${v_n}$ denotes the set of normalized eigenvectors
of $N$. Let $T$ be a subset of conjugate operators of $N$. A classification of
$T$ are given as $T=T_{\{0\}}\cup T_{D\setminus \{0\}}\cup T_{\partial D}$, and
$T_A\in T_{\{0\}}$ and $T_G\in T_{\partial D}$ are shown. Here the
classification is specified by a pair of parameters $(\omega,m)\in C\times N$.
Finally the time evolution $T_{\omega,m}(t)=e^{itN} T_{\omega,m}e^{-itN}$ for
$T_{\omega,m}\in T$ is investigated, and show that $T_{\omega,m}(t)$ is
periodic.
